Trig starts on Monday

Starting December 11th we will be beginning our unit on trig functions. It might be a good idea for you to review your unit circle and trig learned in Geometry. I have assigned a unit circle lesson on khan academy and am including links to a blank unit circle and a filled in unit circle below. You will need to have your unit circle memorized!

Blank unit circle
Filled in unit circle

Here is a quick review from the website Math is Fun: Unit circle review

Footnote: where do the values come from?

We can use the equation x² + y² = 1 to find the lengths of x and y (which are equal to cosand sin when the radius is 1):

45 Degrees

For 45 degrees, x and y are equal, so y=x:

x² + x² = 1

2x² = 1

x² = ½

x = y = √(½)

60 Degrees

Take an equilateral triangle (all sides are equal and all angles are 60°) and split it down the middle.

The "x" side is now ½,

And the "y" side is:

(½)² + y² = 1

¼ + y² = 1

y² = 1-¼ = ¾

y = √(¾)

30 Degrees

30° is just 60° with x and y swapped, so x = √(¾) and y = ½

And:

√(½) is also this:
And √(¾) is also this:

And here is the result (same as before):

Angle	Sin	Cos	Tan=Sin/Cos
30°			1√3 = √33
45°			1
60°			√3